diff mbox series

gpio: acpi: work around false-positive -Wstring-overflow warning

Message ID 20170906154756.2133726-1-arnd@arndb.de
State Accepted
Commit 3a583db3ae164dd9970e332389c672e4cf686f6b
Headers show
Series gpio: acpi: work around false-positive -Wstring-overflow warning | expand

Commit Message

Arnd Bergmann Sept. 6, 2017, 3:47 p.m. UTC
gcc-7 notices that the pin_table is an array of 16-bit numbers,
but fails to take the following range check into account:

drivers/gpio/gpiolib-acpi.c: In function 'acpi_gpiochip_request_interrupt':
drivers/gpio/gpiolib-acpi.c:206:24: warning: '%02X' directive writing between 2 and 4 bytes into a region of size 3 [-Wformat-overflow=]
   sprintf(ev_name, "_%c%02X",
                        ^~~~
drivers/gpio/gpiolib-acpi.c:206:20: note: directive argument in the range [0, 65535]
   sprintf(ev_name, "_%c%02X",
                    ^~~~~~~~~
drivers/gpio/gpiolib-acpi.c:206:3: note: 'sprintf' output between 5 and 7 bytes into a destination of size 5
   sprintf(ev_name, "_%c%02X",
   ^~~~~~~~~~~~~~~~~~~~~~~~~~~
    agpio->triggering == ACPI_EDGE_SENSITIVE ? 'E' : 'L',
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    pin);
    ~~~~

As suggested by Andy, this changes the format string to have a fixed length.
Since modifying the range check did not help, I also opened a bug against
gcc, see link below.

Fixes: 0d1c28a449c6 ("gpiolib-acpi: Add ACPI5 event model support to gpio.")
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://patchwork.kernel.org/patch/9840801/
Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82123
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

---
 drivers/gpio/gpiolib-acpi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

-- 
2.9.0

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Comments

Mika Westerberg Sept. 7, 2017, 6:50 a.m. UTC | #1
On Wed, Sep 06, 2017 at 05:47:45PM +0200, Arnd Bergmann wrote:
> gcc-7 notices that the pin_table is an array of 16-bit numbers,

> but fails to take the following range check into account:

> 

> drivers/gpio/gpiolib-acpi.c: In function 'acpi_gpiochip_request_interrupt':

> drivers/gpio/gpiolib-acpi.c:206:24: warning: '%02X' directive writing between 2 and 4 bytes into a region of size 3 [-Wformat-overflow=]

>    sprintf(ev_name, "_%c%02X",

>                         ^~~~

> drivers/gpio/gpiolib-acpi.c:206:20: note: directive argument in the range [0, 65535]

>    sprintf(ev_name, "_%c%02X",

>                     ^~~~~~~~~

> drivers/gpio/gpiolib-acpi.c:206:3: note: 'sprintf' output between 5 and 7 bytes into a destination of size 5

>    sprintf(ev_name, "_%c%02X",

>    ^~~~~~~~~~~~~~~~~~~~~~~~~~~

>     agpio->triggering == ACPI_EDGE_SENSITIVE ? 'E' : 'L',

>     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

>     pin);

>     ~~~~

> 

> As suggested by Andy, this changes the format string to have a fixed length.

> Since modifying the range check did not help, I also opened a bug against

> gcc, see link below.

> 

> Fixes: 0d1c28a449c6 ("gpiolib-acpi: Add ACPI5 event model support to gpio.")

> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

> Link: https://patchwork.kernel.org/patch/9840801/

> Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82123

> Signed-off-by: Arnd Bergmann <arnd@arndb.de>


Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>

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diff mbox series

Patch

diff --git a/drivers/gpio/gpiolib-acpi.c b/drivers/gpio/gpiolib-acpi.c
index 4d2113530735..eb4528c87c0b 100644
--- a/drivers/gpio/gpiolib-acpi.c
+++ b/drivers/gpio/gpiolib-acpi.c
@@ -203,7 +203,7 @@  static acpi_status acpi_gpiochip_request_interrupt(struct acpi_resource *ares,
 
 	if (pin <= 255) {
 		char ev_name[5];
-		sprintf(ev_name, "_%c%02X",
+		sprintf(ev_name, "_%c%02hhX",
 			agpio->triggering == ACPI_EDGE_SENSITIVE ? 'E' : 'L',
 			pin);
 		if (ACPI_SUCCESS(acpi_get_handle(handle, ev_name, &evt_handle)))